Light vs Kira?

How much of Kira do you think makes up Light Yagami? In other words, do you think Kira is Light Yagami just with a different name, or is Kira simply a persona brought out by the death note? Further more, how much influence do you think the death note or being Kira had on Light, or was he always Kira in some way? I have my own thoughts but I’m interested to hear your opinions!